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Hey guys,

My home theater PC is running an old Intel Q9550. It has a pretty massive CPU cooler with the fan plugged directly into the motherboard.

I've noticed that when the CPU is being used heavily, the temps get up past 70 degrees Celsius, but the CPU fan doesn't spin any faster than 1200RPM. I've tried using Speedfan to manually set the fan speed higher, but it doesn't work.

I also tried setting the fan speed setting in BIOS to "performance mode" but it makes no difference.

Anyone have any ideas of what I could try next?

Thanks in advance!

Are you sure your fan goes higher than 1200RPMs?

I have a Scythe Mugen-2 and the fan that came with it tops out at 1300RPMs.

What CPU cooler are you using?

Worst case scenario you have to replace the fan if the cooler accepts standard fans and it doesn't use some intricate custom design to fasten the fan, in which case you'll need to buy a fan exactly like the original, if it's still being manufactured.

I doubt the BIOS is at fault here, but you could always use another fan to test it. If the motherboard CPU cooler fan header turns out to be the culprit, you could improvise something like removing the cooler fan from the heatsink and placing it somewhere else inside the case (while still being attached to the header) and install another fan on the heatnsik and power it directly from the powersupply via a molex to 4 pin adaptor.

If you're sure the fan is functioning as intended, the first thing I'd do is remove the whole heatsink.
I'd clean the TIM material from both the base of the heatsink and the CPU. Apply new TIM (Arctic Silver 5 or whatever your preference is). Then re-seat the heatsink/fan.
If temperatures still don't improve, you'll either need to look into increasing airflow in the system case, or have to invest in a higher performance CPU cooler.
That would be my systematic approach.
Good luck.

Being an old system, I would expect you to be familiar with your CPU's normal temps and your HSF's normal RPM. If you suspect the HSF to be running slower than normal, you might want to try cleaning it all over and adding a few drops of oil (sewing machine oil would be ok, I guess) into the fan to lubricate it a bit. Put it back with fresh thermal compound, and see if it improves. If it still doesn't, you may need to test another HSF to see if it a new HSF brings the temp down. Oh, and yeah, make sure you're using quality thermal compound. I've relied too long on cheap TIM and found out that quality TIM really makes a difference when the going gets tough.

I think the fan should spin faster - When I first boot the computer, it spins extremely fast for about a second before settling down.

The cooler is clean, although I don't have any case fans so that could be an issue. Also, I only installed the cooler today, so it got a fresh blob of thermal paste.. so don't think that's the issue.

Thanks for the tips.

I assume you have not added or removed any case fans before you noticed this situation. If it's been running for years without adequate case fans, why would the temps go that high now? Haven't you noticed this before? Is it getting hotter in your area? I would assume the HSF is at fault if no other factor was changed.

ronch wrote:

I assume you have not added or removed any case fans before you noticed this situation. If it's been running for years without adequate case fans, why would the temps go that high now? Haven't you noticed this before? Is it getting hotter in your area? I would assume the HSF is at fault if no other factor was changed.

The parts may be old, but it's a new build.. I put it together out of bits I had lying around.

Might put another case fan in and see how that goes

Oh, I see. It's technically a new build -- with old parts. Still, 70C seems a little high for a Core 2 Quad, a 95w TDP part. Even just adding a couple of case fans, one at the rear of the case and another on the side, should at least put temps in the 50's. My Phenom II was a higher TDP part using only the small stock fan. Two case fans, ambient temp is around 32C, load temp reaches about 54C. For your reference.

Have you verified that you're running the latest BIOS for that board?

Still no mention of the CPU cooler model in question.

Edited, I thought you were using the stock cooler.

It just sounds like a crap heatsink: Massive, 1100RPM and still running hot?
Get a proper, yet inexpensive one, like the CM TX3, Hyper 212 or 412s

Chrispy_ wrote:

It just sounds like a crap heatsink: Massive, 1100RPM and still running hot?
Get a proper, yet inexpensive one, like the CM TX3, Hyper 212 or 412s

I would agree with you, except for:

suicidemonkey wrote:

I think the fan should spin faster - When I first boot the computer, it spins extremely fast for about a second before settling down.

This really sounds like a problem with the fan speed control on the motherboard. If it is running hot, the fan should be spinning up.

Or maybe the 70C reading is incorrect. @suicidemonkey - What are you using to read that 70C temp, and is it in general agreement with the temps reported in the BIOS? (Yeah, you can't really look at BIOS temp readings with the CPU under load, but you can at least verify that the temperature readings are similar at idle.)

Yeah to explain my reasoning, a fan that is "sticky" but not failed will spin slower than it is designed to, hence the inadequate cooling.

At bootup it could be spinning up under full voltage, but the gunked-up bearings mean this is only 1800RPM or something, rather than the 3500RPM it is supposed to be.
The fan controller might be applying the right voltage for a 70C chip (enough to normally boost the fan to 2500RPM or similar) but the knackered fan is what is holding everything back.

I dunno, depends if the OP feels the fan spins freely by itself or not. Cheap sleeve-bearing fans just get slower and slower until they barely spin at all - I hate 'em; Fluid-dynamic or double ball-bearing all the way!

Is there anywhere in the BIOS fan speed settings where you can set a target CPU temp?

just brew it! wrote:

Or maybe the 70C reading is incorrect. @suicidemonkey - What are you using to read that 70C temp, and is it in general agreement with the temps reported in the BIOS? (Yeah, you can't really look at BIOS temp readings with the CPU under load, but you can at least verify that the temperature readings are similar at idle.)

Most mobos include BIOS software that will allow you to see what CPU temp the BIOS is reporting in Windows. If not, a more primitive approach would be to touch the heatsink, at 70C it should feel pretty warm.

DPete27 wrote:

Most mobos include BIOS software that will allow you to see what CPU temp the BIOS is reporting in Windows. If not, a more primitive approach would be to touch the heatsink, at 70C it should feel pretty warm.

Unless the problem is with the thermal interface between the heatsink and the CPU, in which case the CPU could be a *lot* hotter than the heatsink.

I have a motherboard where the CPUTIN sensor seems to get "stuck" at 124°C (254°F, a suspicious number for other reasons) once it goes through a sleep/wake cycle (only a full boot fixes it). The individual core and package sensors on CPU proper remain valid and indicate correct temperature, so I just ignore it, but if I was trying to use that reading as the basis for setting fan speed it would be a problem. Not saying that's what's going on here, just that sensors aren't infallible and you need to verify things independently if you can.

just brew it! wrote:

DPete27 wrote:

Most mobos include BIOS software that will allow you to see what CPU temp the BIOS is reporting in Windows. If not, a more primitive approach would be to touch the heatsink, at 70C it should feel pretty warm.

Unless the problem is with the thermal interface between the heatsink and the CPU, in which case the CPU could be a *lot* hotter than the heatsink.

Yeah, if that "fresh blob of thermal paste" was too much of a blob, it could be a problem. If the heatsink isn't warm when the CPU thinks it is 70°C, it's a problem.

Simple suggestion that I didn't see above, make sure your fan is really plugged into the CPU fan header and not a system fan one, I've seen a few mobos where they are really close physically. Probably not the issue since you are reading the RPMs and presumably have the fan name right on the screen but maybe...?

Not too sure what the cooler is. I got it from a friend. I might just buy a new one, I've had good experiences with a few CM coolers.

aS for the temps, I verified them in HW Monitor, Real Temp and Fan Speed, and they all read about the same. It also reads about 50 degrees celcius in BIOS (which is the latest version, btw).

Thanks for all the tips. Next step - new CPU Cooler!

I'm currently about to build a new video editing PC when Intel releases a 6-core Haswell CPU, so hopefully I won't need to worry about this for too much longer